CVE-2026-14541: An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initia
An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-14541
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-145410.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 19% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-14541 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for An authentication bypass
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- mediumCVE-2026-67337: better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability whe…nvd · 2026-08-01
- highCVE-2026-67328: @better-auth/sso versions before 1.6.21 contain multiple authentication bypass vulnerabilities…nvd · 2026-08-01
- criticalCVE-2026-15964: The Single Sign On For TNG plugin for WordPress is vulnerable to Authentication Bypass via una…nvd · 2026-08-01
- unknownCVE-2026-52134: An issue in the parseGoosePayload() function (/goose/goose_receiver.c) of libiec61850 v1.6 all…nvd · 2026-07-31
- criticalCisco Secure Firewall Management Center Software Authentication Bypass Vulnerabilitycisco-psirt · 2026-07-31
- highCVE-2026-66420: MeshCentral 1.1.21 contains a cross-site WebSocket hijacking protection bypass vulnerability t…nvd · 2026-07-30
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